Telemetry stream: GET /api/telemetry + MCP get_telemetry (#16)

src/mesh/mesh.controller.ts

@@ -183,6 +183,40 @@ export class MeshController {
     return this.mesh.messages();
   }
 
+  @Get('telemetry')
+  @ApiOperation({
+    summary: 'Telemetry history (last 100)',
+    description:
+      "TELEMETRY_APP packets from any node, newest first. Device metrics (uptime/battery/voltage/channel+air utilization) and environment sensor readings where nodes have them; kind is the meshtastic.Telemetry oneof case name — deviceMetrics, environmentMetrics, airQualityMetrics, powerMetrics, localStats, healthMetrics, hostMetrics or trafficManagementStats — and data carries that variant's payload (proto uint64 fields as decimal strings). In-memory only (last 100), reset on every bridge reconnect.",
+  })
+  @ApiResponse({
+    status: 200,
+    description: 'Telemetry records newest first',
+    example: [
+      {
+        from: 987654321,
+        at: 1758000123456,
+        kind: 'deviceMetrics',
+        data: {
+          batteryLevel: 87,
+          voltage: 4.1,
+          channelUtilization: 12.5,
+          airUtilTx: 3.2,
+          uptimeSeconds: 86400,
+        },
+      },
+      {
+        from: 123456789,
+        at: 1758000000000,
+        kind: 'environmentMetrics',
+        data: { temperature: 21.5, relativeHumidity: 48 },
+      },
+    ],
+  })
+  telemetry() {
+    return this.mesh.telemetry();
+  }
+
   @Get('nodes')
   @ApiOperation({
     summary: 'Known mesh nodes (lean summaries)',